Quantcast ATI AIW 7500 VE PCI vs. Diamond VC500 for LaserDisc - Page 2 - digitalFAQ Forum
Go Back    Forum > Digital Video > Video Project Help > Capture, Record, Transfer

Reply
 
LinkBack Thread Tools
  #21  
03-20-2017, 02:06 PM
msgohan msgohan is offline
Free Member
 
Join Date: Feb 2011
Location: Vancouver, Canada
Posts: 1,323
Thanked 328 Times in 273 Posts
You must crop all borders when relying upon VirtualDub's histogram. I see that while Sanlyn's guide mentions this, he doesn't specify that it's an absolute requirement. And I recommend you overcrop while measuring, since there is little downside to doing so. Too bad it's too late for him to edit the post now. I think he did say that you should crop when teaching you directly in another thread.

The reason is that the "black" borders are actually superblack. They're horizontal blanking and they're at blanking level, which in the case of our video system means they're 7.5 IRE darker than video black. They should be at digital 0. So if you leave them in the image while using VirtualDub's histogram, they should be red. Bringing them out of the red area means you're washing out your entire picture.

For PAL and NTSC-J, this theoretically doesn't matter since there is no pedestal and blanking = video black = 0 IRE = digital 16. I would still crop them while adjusting regardless, otherwise you're still calibrating to the non-video area and assuming that whoever made the video set black in exactly the perfect, technically-correct spot.

Quote:
Originally Posted by metaleonid View Post
So in short, do I need to adjust brightness/contrast during the capture so that Loose Minimum has the value 16?
Essentially, yes. On a totally black screen, Loose Minimum "should" be 16-17.* On the waveform display, you would see a line hovering along the bottom brownish edge. Then the same thing for whites, but in reverse: Loose Max ~235. But I personally prefer to rely more on Maximum ~235 and let Loose Max hover lower, since clipped brights bother me much more than crushed blacks.

* For retail tapes & LDs, you will find that some black screens have different levels than others. You want the one that actually matches your program content. So don't really solely on a black screen at the start of a disc. Check dark scenes in the video too.

Quote:
Or can this be adjusted as post processing?
It can be, but your whole goal was to optimize the proc amp setup. Stretching it afterwards will tend to introduce more banding. And like with audio, the SNR would be lower.

Last edited by msgohan; 03-20-2017 at 02:17 PM.
Reply With Quote
The following users thank msgohan for this useful post: metaleonid (03-20-2017)
Someday, 12:01 PM
admin's Avatar
Ads / Sponsors
 
Join Date: ∞
Posts: 42
Thanks: ∞
Thanked 42 Times in 42 Posts
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
Issues with Legacy VC500-USB mtetreault Capture, Record, Transfer 12 07-02-2019 06:37 PM
Diamond VC500 won't capture with VirtualDub and Win10 SoManyTapes Capture, Record, Transfer 5 01-03-2017 07:17 AM
Diamond ATI HD 750 not compatible with AVI files? VivianMitchell Capture, Record, Transfer 2 08-21-2014 11:54 PM
VHS capture to AVI with VC500 -- thoughts? jmt0 Capture, Record, Transfer 15 01-14-2014 08:57 AM
ATI Diamond 750 USB vs ATI 600 USB card? lordsmurf Capture, Record, Transfer 1 08-23-2010 06:35 AM

Thread Tools



 
All times are GMT -5. The time now is 03:39 PM